A study on the urban growth during the time between 2000 to 2016 was undertaken in a forest locality of the republic of Congo, the town of Ouesso. Landsat images covering this period had been selected and treated thanks to the software ENVI 4.6.1 and ArcGis 10.2. Supervised classification was used and applied to the zone of study. The results of this study indicate that the surface of the city passed from 608.375 ha in 2000 to 1527 ha in 2016. The losses of the forests due to the urban growth passed from 261.63 ha during the time of 2000-2014 to 657.03 ha during the time of 2014 to 2016. The demographic growth, poverty, agriculture, residential spreading out and the accelerated municipalization which took place in this locality would explain the losses of the forest surfaces observed in this locality. The anarchistic urban growth in wet tropical zone could be the source of significant flows of GES following the changes of use of the grounds.